Signal transmission structure, package structure and bonding method thereof

Abstract

A signal transmission structure including a first signal pad, a first reference plane surrounding the first signal pad, a second signal pad, a second reference plane surrounding the second signal pad, an electric conductive element, and a conductive wall is provided. The second reference plane is parallel to the first reference plane, and the electrical conductive element is connected between the first signal pad and the second signal pad to transmit a signal. The conductive wall is connected between the first reference plane and the second reference plane and surrounding the electrical conductive element. Furthermore, a package structure applying to the signal transmission structure and a bonding method thereof are provided.

1. A package structure, comprising:
 a first substrate having a first signal pad, a first reference plane and a first solder mask layer, wherein the first reference plane is surrounding the first signal pad and the first solder mask layer is disposed on the first reference plane and the first signal pad is exposed by the first solder mask layer, the first solder mask layer having a first annular opening surrounding the first signal pad to expose a part of the first reference plane; 
 a second substrate having a second signal pad, a second reference plane and a second solder mask layer, wherein the second reference plane is surrounding the second signal pad and the second solder mask layer is disposed on the second reference plane and the second signal pad is exposed by the second solder mask layer, the second solder mask layer having a second annular opening surrounding the second signal pad to expose a part of the second reference plane; 
 an electrical conductive element connecting between the first signal pad and the second signal pad so as to transmit a signal; and 
 a conductive wall connecting between the first reference plane exposed by the first solder mask layer and the second reference plane exposed by the second solder mask layer as well as surrounding the electrical conductive element. 
 
     
     
       2. The package structure of  claim 1 , wherein the first reference plane and the second reference plane are ground planes. 
     
     
       3. The package structure of  claim 1 , wherein the first reference plane and the second reference plane are power planes. 
     
     
       4. The package structure of  claim 1 , wherein the electrical conductive element comprises a metal ball. 
     
     
       5. The package structure of  claim 1 , wherein the signal has a frequency more than 1 GHz. 
     
     
       6. The package structure of  claim 1 , wherein the first substrate is a circuit substrate or a printed circuit board. 
     
     
       7. The package structure of  claim 1 , wherein the second substrate is a circuit substrate or a printed circuit board. 
     
     
       8. The package structure of  claim 1 , wherein the conductive wall forms a sealed space therein.